DDE

Dynamic Data Exchange (DDE) is a standard inter-application communication protocol built into Microsoft Windows operating systems and supported by many applications that run under Windows. DDE takes data from one application and gives it to another application. It allows Windows programs that support DDE to exchange data between themselves.

By specifying an application, topic, and item, a client application can exchange data with a server application.

DDE works like a conversation between two people. The people represent the different applications running under Windows, and the data they share is what they are talking about.

Applications using DDE to talk to RSLinx Classic do not care what kind of data they are getting. All they know is there is a DDE link, and that link is providing data. What that data is and how it will be used is immaterial to the receiving application.

For example, if you have a DDE link from RSLinx Classic to an Excel spreadsheet, Excel does not know that you are sending a counter value into a spreadsheet. All Excel sees is data.

For example,

RSLINX

is the application name,

PLC5TOPIC1

is an example topic name, and

C5:0.ACC

is an example item, in this case a counter accumulator in an Allen-Bradley PLC-5.